Cervical Plexus Block

The cervical plexus block is most commonly associated with analgesia for carotid endarterectomy; however, its clinical utility extends beyond this single indication. Recent literature has demonstrated its effectiveness in procedures involving the clavicle, airway, thyroid, submandibular gland, and various neck dissections. It has also shown potential in the management of certain headache syndromes.

Despite the intricate anatomy and complex innervation of the cervical region, the cervical plexus block itself is relatively straightforward to perform, provided that key safety considerations are observed. The term “cervical plexus block” encompasses three distinct approaches: superficial, intermediate, and deep. While the superficial and deep techniques are well established in clinical practice and literature, the intermediate block remains less well-defined and lacks sufficient peer-reviewed evidence; thus, it is not addressed in detail here.

In many clinical scenarios, a combination of superficial and deep cervical plexus blocks is employed to achieve analgesia of the peri-clavicular and cervical regions. Studies suggest that this combined approach offers superior analgesia compared to either block performed in isolation.

Notably, ultrasound guidance has not demonstrated a significant improvement in success rates for this block. However, it is widely recognized for its role in enhancing safety by reducing the risk of inadvertent intravascular injection and unintended nerve injury.

When planning for regional anesthesia in these procedures, collaboration with the surgical team is essential. Patients should also be informed that supplemental local infiltration may be necessary to achieve complete surgical anesthesia.

Distribution of the superficial cervical plexus

It is important to recognize that several critical structures lie in close proximity to the target area for cervical plexus blocks. These include the phrenic nerve (located just posterior to the great vessels), the vagus nerve (positioned between the internal jugular vein and the carotid artery), and the major vascular structures of the neck. Due to this anatomical relationship, meticulous technique is essential. Slow, deliberate injections with frequent aspiration are crucial to minimizing the risk of intravascular injection and preventing nerve injury. Injection should cease immediately if the patient experiences pain or paresthesia.

Superficial Cervical Plexus Block

The superficial cervical plexus block is technically straightforward. The posterior border of the clavicular head of the sternocleidomastoid muscle is identified, prepped, and marked. A small-gauge needle is used to raise a skin wheal at the midpoint of this border. Subsequently, a long, thin needle is advanced approximately 0.5–1 cm beneath the skin to infiltrate along the marked line. Infiltration should extend both superiorly and inferiorly relative to the initial skin wheal. A total of approximately 10 mL of local anesthetic is typically sufficient. Refer to Gallery 15.1 for a step-by-step visual reference. The accompanying image illustrates the key landmarks and injection technique for the superficial cervical plexus block.

Deep Cervical Plexus Block

The deep cervical plexus originates from the anterior rami of spinal nerves C2 through C4. Effective blockade requires local anesthetic deposition near these cervical roots. Given that the roots may be enclosed in dura, careful aspiration for cerebrospinal fluid is essential to avoid the rare but serious complication of total spinal anesthesia.

Landmark identification begins at the mastoid process. A line is drawn from this point to the base of the neck, approximately 1–2 cm posterior to the posterior border of the sternocleidomastoid muscle. The transverse processes of C2 through C4 should be palpated along this line and marked. After sterile preparation, skin wheals are raised over each mark.

A blunt needle is then inserted to contact the transverse process at each level. The needle is gently walked inferiorly along the bone to the appropriate location. After negative aspiration, approximately 5 mL of local anesthetic is deposited at each level. Gallery 19.1 and 19.2 provide visual guidance for this technique, including the placement of skin wheals and the needle positioning for the C2 transverse process. Throughout the procedure, patient feedback and careful aspiration are critical to ensuring safe and effective block performance.

Ultrasound-Guided Superficial Cervical Plexus Block

Incorporating ultrasound guidance into the superficial cervical plexus block enhances the ability to identify vascular structures and optimize needle placement, thereby improving the safety and precision of the technique. The block may be performed using either a short-axis or long-axis approach. The long-axis view can facilitate a more continuous spread of local anesthetic; however, caution is advised when using larger volumes, as unintended spread to adjacent anatomical structures may occur.

After appropriate patient positioning, the neck is prepared with an antiseptic solution. Local anesthetic (5 mL of 2% lidocaine with epinephrine) is infiltrated at the marked posterior border of the sternocleidomastoid (SCM) muscle. Using a linear transducer (depth setting 2–3 cm), a long-axis view of the posterior border of the SCM is obtained. A block needle is introduced in-plane, and its full length is visualized as it advances along the fascial plane.

Hydrodissection is then performed using 10 mL of a long-acting local anesthetic such as 0.2% ropivacaine. For prolonged analgesia, especially in procedures like bilateral neck lifts, this block can be extended using liposomal bupivacaine (e.g., 10 mL Exparel), mixed with 5 mL of bupivacaine (Marcaine) and 5 mL of normal saline or lactated Ringer’s, for a total of 20 mL. This mixture may be used for bilateral superficial plexus blocks or combined with a unilateral deep cervical plexus block, depending on the clinical context.

This technique is performed within the superficial cervical plexus fascial plane. Refer to Gallery 15.3 for step-by-step sonographic images, and Video 15.1 for a demonstration of in-plane needle placement in the long-axis approach.

Alternatively, a short-axis view may be employed. This approach offers the advantage of clearly visualizing adjacent anatomical structures, including vascular elements and nerves, thereby helping to avoid inadvertent needle contact or local anesthetic spread to undesired areas. The ultrasound scan is initiated similarly to those used for interscalene or stellate ganglion blocks, with the great vessels of the neck readily identifiable. Following skin antisepsis and local infiltration, the needle is inserted in-plane, posterior to the SCM border, under direct visualization.